Thread: 81 Range Rover 3.5 4 speed manual. What RPM at 100K is norm?

welcome to the site mate

and also welcome to the landy family :wink:


in regards to your question, i cant help you there 8O

but hang tight and the forum guru's will tell you shortly


ps hope all goes well with your rangie

also pop a location in your profile

Thanks for the warm welcome...


I will update my profile...

ha...I just noticed your location hiline...

that makes 4 of us now

It depends on the year model. the models up to 1980 had a low high range gear in the transfer, I do not remember which and if I recall revved at about 3500- 3600 at 100Kmh.
1981 had a considerably higher(and quieter) high range gear and revved lower . Again this is many years ago but I think about 3300.

Regards Philip A

OK I knew I was wrong as soon as I posted this.
Here goes.
According to a web calculator the high ratios are 1.174 ( I presume up to 80 but it doesn't say)
and 1.113 ( I assume 81)
Went to a US rev calculator and input 29.5 inches tyre diameter for a 205x16 and 3.54 for the diff ratio.

Comes to 2419 RPM X 1.174 = 2839 RPM.
With the 1.113 is 2692 RPM.

Originally posted by PhilipA
OK I knew I was wrong as soon as I posted this.
Here goes.
According to a web calculator the high ratios are 1.174 ( I presume up to 80 but it doesn't say)
and 1.113 ( I assume 81)
Went to a US rev calculator and input 29.5 inches tyre diameter for a 205x16 and 3.54 for the diff ratio.

Comes to 2419 RPM X 1.174 = 2839 RPM.
With the 1.113 is 2692 RPM.

My 1976 did 2500rpm @80kph

Calculate kph/1000rpm using this

kph/1000rpm =60000/(gear ratio X Transfer X diff X tyre rev/km)

205R16 = 448rev/km
750R16 = 409rev/km

a 1976 RR 4th gear = 1:1
high range = 1.113:1
diff = 3.54:1

which gave 34.0kph/1000rpm for 4th high on 205R16



Bushie

Thanks for the information. Seeming as though I am still learning how everything feels and acts in the rangie I wasn't sure what to expect the engine to rev at 100 kph.

I thought it may be a little high for a v8 to happily tick over at for long periods of time. But I suppose the fact that there are still so many on the road seems to suggest they will do ths happily.

When I bought the car, the mechanic sugested that the gearbox was not the original becuase it had a short shift between gates. He suggested the 81 gearbox had a longer shift between gears. So going by this it is quite possible that it is a high ratio box.

I suppose it leads me to the question of whether a 5 speed box is a better option or not. Reading other post seems to suggest that the 5speed box was pretty weak. If that is the case should I stick with the higher revs at 100 Kph for the sake of having a strong gearbox.